1. Field of the Invention
The present invention relates to a pull-out device which includes at least one carcass rail and at least one pull-out rail, with the carcass and pull-out rails forming together a rail pair, and a blocking device for retaining the carcass and pull-out rails in a respective relative position of the carcass rail and the pull-out rail, with the blocking device having at least one stationary tooth rack which extends parallel to the carcass and pull-out rails, and a tooth segment operatively connected with the at least one pull-out rail and engageable with the tooth rack for blocking displacement of the at least one pull-out rail relative to the at least one carcass rail.
2. Description of the Prior Art
U.S. Pat. No. 4,950,123 discloses a pull-out device of the type described above and used together with a cargo platform of a truck. The device provides for pulling the cargo platform rearward which facilitates loading of the cargo. The rear ends of the pull-out rails of this pull-out device are connected with a transverse spar. A pivotable lever is attached to the transverse spar. The lever is also connected with horizontal bolts which extend transverse to the pull-out device. The lever is actuated by an actuation rod which extends parallel to the pull-out device. The bolts, an end of which is located in respective bores formed in the vertical web of the pull-out rail, are displaced axially upon the pivotal movement of the lever. The respective carcass rail and an intermediate rail, which is also provided in this device, have each a bore into which the bolt can extend. Upon the bolt extending into these bores, the displacement of rails relative to each other is blocked. For the bolt to extend into the bores formed in the carcass and intermediate rails, these bores should be aligned with each other.
A pull-out device for a cargo platform of a truck, which is provided with a blocking device, is also disclosed in European Publication EP 314 172 A2. The blocking device includes spring-biased bolts and a tow bar for axially displacing the bolts into bores formed in the vertical web of the stationary carcass rail. The axially displaceable bolts are provided on the pull-out platform. When the tow bar is operated, the cargo platform should not move in order to insure the displacement of the bolts into the respective bores.
Austrian Publication A 2207/96 also discloses a spring-biased bolt operated by an actuation bar extending parallel to the pull-out rails. The bolt cooperates with a strip which is provided with an appropriate hole, is secured to the stationary carcass rail, and extends parallel to the carcass rail.
The pull-out devices are used in motor vehicles for pulling out the cargo platform. Such platforms are primarily used in ambulance vehicles and often carry heavy apparatuses and devices. When such platforms can be pulled-out, an access to these apparatuses and devices is noticeably facilitated. The workshop trucks likewise have a number of drawers which are loaded with heavy tools. In all these cases, it should be insured that the pull-out devices, which are, generally, easily displaceable, are not automatically displaced under action of accelerating forces generated during movement of a vehicle.
It also known to provide pull-out devices which are used with furniture, with devices which retain a pull-out furniture piece in a predetermined or desired position. One of such devices is disclosed in U.S. Pat. No. 3,700,301, with the device being associated with so-called ball guides. Above a ball guide, which connects a wall of a furniture carcass of a piece of furniture with the pull-out furniture piece, a toothed strip is secured to the furniture carcass wall. The pull-out furniture piece is provided with a toothed segment which is displaced by a pivotal level into and out of engagement wit the toothed strip. The lever has one of its ends displaceable in a vertical slideway. A switch rod provided to this end extends parallel to the toothed strip and is displaced against a spring biasing force. The switch rod is provided on the pull-out furniture piece. This blocking mechanism is unprotected from the environment and can only be used in closed spaces. This mechanism is not suitable for use in motor vehicles. If used in motor vehicle, this mechanism would be rapidly soiled and thereby damaged.
A construction, similar to that of U.S. Pat. No. 3,700,301, is also disclosed in U.S. Pat. No. 2,739,027. A bolt, which is arranged at one end of a pivotal bell-crank lever, is used as a locking member cooperating with a stationary tooth rack provided on furniture body. Opposite end of the bell-crank lever engages a switch rod which is supported on a pull-out rail and is displaceable against a biasing force of a spring. The blocking mechanism, which is disclosed in U.S. Pat. No. 2,739,027, is located between a carcass furniture wall and a side wall of the pull-out furniture piece and is likewise nor protected from the surrounding environment.
Finally, an appropriate blocking device for a pull-out mechanism of a tall cupboard is disclosed in U.S. Pat. No. 3,367,732. Here, for retaining the pull-out furniture piece in a predetermined pull-out position, there is provided a drive including a level wheel which is supported in a cantilever fashion and against which a stop is pressed by a spring force. This blocking mechanism is arranged beneath the bottom of the pull-out furniture piece and, thereby, is better protected from the environment than the previously described mechanisms. However, this construction is very expensive and did not find a practical application.
Accordingly, an object of the present invention is a pull-out device adapted to be used with motor vehicles and provided with a blocking device which is adequately protected against soiling and an outside mechanical action. Another object of the present invention is a blocking device of the above-described type which for reducing friction, is lubricated, with the lubricated parts being spaced from the region of the teeth engagement.